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Objective: To determine whether rapid access chest pain clinics are clinically effective by comparison of coronary event rates in patients diagnosed with angina with rates in patients diagnosed with non-cardiac chest pain and the general population. Design: Multicentre cohort study of consecutive patients with chest pain attending the rapid access chest pain clinics (RACPCs) of six hospitals in England. Participants: 8762 patients diagnosed with either non-cardiac chest pain (n = 6396) or incident angina without prior myocardial infarction (n = 2366) at first cardiological assessment, followed up for a median of 2.57 (interquartile range 1.96-4.15) years. Main outcome measures: Primary end point-death due to coronary heart disease (international Classification of Diseases (ICD)10 120-125) or acute coronary syndrome (non-fatal myocardial infarction (ICD10 121-123), hospital admission with unstable angina (124.0, 124.8, 124.9)). Secondary end points-all-cause mortality (lCD 120), cardiovascular death (ICD10 100-199), or non-fatal myocardial infarction or non- fatal stroke (160-169). Results: The cumulative probability of the primary end point in patients diagnosed with angina was 16.52% (95% confidence interval (CI) 14.88% to 18.32%) after 3 years compared with 2.73% (95% CI 2.29% to 3.25%) in patients with non-cardiac chest pain. Coronary standardised mortality ratios for men and women with angina aged <65 years were 3.52 (95% CI 1.98 to 5.07) and 4.39 (95% CI 1.14 to 7.64). Of the 599 patients who had the primary end point, 194 (32.4%) had been diagnosed with non-cardiac chest pain. These patients were younger, less likely to have typical symptoms, more likely to be south Asian and more likely to have a normal resting electrocardiogram than patients with angina who had the primary end point. Conclusion: RACPCs are successful in identifying patients with incident angina who are at high coronary risk, but there is a need to reduce misdiagnosis and improve outcomes in patients diagnosed with non-cardiac chest pain who accounted for nearly one third of cardiac events during follow-up. [ABSTRACT FROM AUTHOR]

To compare major determinants of myocardial oxygen demand (heart rate, blood pressure and rate pressure product) in patients with and without diabetes admitted with acute coronary syndromes. A cross-sectional study of the relation between diabetes and haemodynamic indices of myocardial oxygen demand in 2542 patients with acute coronary syndromes, of whom 1041 (41.0%) had acute myocardial infarction and 1501 (59.0%) unstable angina. Of the 2542 patients, 701 (27.6%) had diabetes. Major haemodynamic determinants of myocardial oxygen demand were higher in patients with than without diabetes: heart rate 80.0 ± 20.4 vs. 75.2 ± 19.2 beats/minute ( P < 0.0001); systolic blood pressure 147.3 ± 30.3 vs. 143.2 ± 28.5 mmHg ( P = 0.002); rate-pressure product 11533 ± 4198 vs. 10541 ± 3689 beats/minute × mmHg ( P < 0.0001). Multiple regression analysis confirmed diabetes as a significant determinant of presenting heart rate [multiplicative coefficient (MC) 1.05; 95% confidence interval (CI) 1.03–1.07; P < 0.0001], rate pressure product (MC 1.09; CI 1.05–1.12; P < 0.0001) and systolic blood pressure, which was estimated to be 3.9 mmHg higher than in patients without diabetes ( P = 0.003). These effects of diabetes were independent of a range of baseline variables including acute left ventricular failure and mode of presentation (unstable angina or myocardial infarction). In acute coronary syndromes, heart rarte and other determinants of myocardial oxygen demand are higher in patients with than without diabetes, providing a potential contributory mechanism of exaggerated regional ischaemia in this high-risk group. Diabet. Med. 21, 1025–1031 (2004) [ABSTRACT FROM AUTHOR]

Objectives: To compare serum potassium concentrations in diabetic and non-diabetic patients in the early phase of acute coronary syndromes.Background: Acute phase hypokalaemia occurs in response to adrenergic activation, which stimulates membrane bound sodium-potassium-ATPase and drives potassium into the cells. It is not known whether the hypokalaemia is attenuated in patients with diabetes because of the high prevalence of sympathetic nerve dysfunction.Methods: Prospective cohort study of 2428 patients presenting with acute coronary syndromes. Patients were stratified by duration of chest pain, diabetic status, and pretreatment with beta blockers.Results: The mean (SD) serum potassium concentration was significantly higher in diabetic than in non-diabetic patients (4.3 (0.5) v 4.1 (0.5) mmol/l, p < 0.0001). Multivariate analysis identified diabetes as an independent predictor of a serum potassium concentration in the upper half of the distribution (odds ratio 1.66, 95% confidence interval 1.38 to 2.00). In patients presenting within 6 hours of symptom onset, there was a progressive increase in plasma potassium concentrations from 4.08 (0.46) mmol/l in patients presenting within 2 hours, to 4.20 (0.47) mmol/l in patients presenting between 2-4 hours, to 4.24 (0.52) mmol/l in patients presenting between 4-6 hours (p = 0.0007). This pattern of increasing serum potassium concentration with duration of chest pain was attenuated in patients with diabetes, particularly those with unstable angina. Similar attenuation occurred in patients pretreated with beta blockers.Conclusion: In acute coronary syndromes, patients with diabetes have significantly higher serum potassium concentrations and do not exhibit the early dip seen in non-diabetics. This may reflect sympathetic nerve dysfunction that commonly complicates diabetes. [ABSTRACT FROM AUTHOR]

Objective To compare short and medium-term prognosis in South Asian and Caucasian patients undergoing percutaneous coronary intervention (PCI) to determine if there are ethnic differences in case death rates. Design Retrospective cohort study. Setting A cardiology referral centre in east London. Patients 9771 patients who underwent PCI from October 2003 to December 2007 of whom 7966 (81.5%) were Caucasian and 1805 (18.5%) were South Asian. Main outcome measures In-hospital major adverse cardiac events (MACE; death, myocardial infarction, stroke and target vessel revascularisation), subsequent revascularisation rates (PCI and coronary artery bypass grafting; CABG) and all-cause mortality during a median follow-up of 2.5 years (range 1.5-3.6 years). Results South Asian patients were younger than Caucasian patients (59.69±0.27 vs 64.69±0.13 years, p<0.0001), and more burdened by cardiovascular risk factors, particularly type II diabetes mellitus (45.9%±1.2% vs 15.7%±0.4%, p<0.0001). The in-hospital rates of MACE were similar for South Asians and Caucasians (3.5% vs 2.8%, p=0.40). South Asians had higher rates of clinically driven PCI for restenosis and subsequent CABG, although Kaplan-Meier estimates of all-cause mortality showed no significant differences; this was regardless of whether PCI was performed post-acute coronary syndrome or as an elective procedure. The adjusted hazard of death for South Asians compared with Caucasians was 1.00 (95% CI 0.81 to 1.23). Conclusion In this large PCI cohort, the in-hospital and longer-term mortality of South Asians appeared no worse than that of Caucasians. South Asians had higher rates of restenosis and CABG during follow-up. Data suggest that the excess coronary mortality for South Asians compared with Caucasians is not explained by differences in case-fatality rates. [ABSTRACT FROM AUTHOR]

Objective To compare short and medium-term prognosis in South Asian and Caucasian patients undergoing percutaneous coronary intervention (PCI) to determine if there are ethnic differences in case death rates. Design Retrospective cohort study Setting A cardiology referral centre in east London Patients 9771 patients who underwent PCI from October 2003 to December 2007 of whom 7966 (81.5%) were Caucasian and 1805 (18.5%) were South Asian Main outcome measures In-hospital major adverse cardiac events (MACE; death, myocardial infarction, stroke and target vessel revascularisation), subsequent revascularisation rates (PCI and coronary artery bypass grafting; CABG) and all-cause mortality during a median follow-up of 2.5 years (range 1.5e3.6 years Results South Asian patients were younger than Caucasian patients (59.6960.27 vs 64.6960.13 years, p<0.0001), and more burdened by cardiovascular risk factors, particularly type II diabetes mellitus (45.9%6 1.2% vs 15.7%60.4%, p<0.0001). The in-hospital rates of MACE were similar for South Asians and Caucasians (3.5% vs 2.8%, p¼0.40). South Asians had higher rates of clinically driven PCI for restenosis and subsequent CABG, although KaplaneMeier estimates of all-cause mortality showed no significant differences; this was regardless of whether PCI was performed post-acute coronary syndrome or as an elective procedure. The adjusted hazard of death for South Asians compared with Caucasians was 1.00 (95% CI 0.81 to 1.23 Conclusion In this large PCI cohort, the in-hospital and longer-term mortality of South Asians appeared no worse than that of Caucasians. South Asians had higher rates of restenosis and CABG during follow-up. Data suggest that the excess coronary mortality for South Asians compared with Caucasians is not explained by differences in case-fatality rates [ABSTRACT FROM AUTHOR]

Background: Shortening prehospital delay has been identified as an important means of improving responses to reperfusion treatment. If this increases the risk profile of the population delivered to hospital, it may paradoxically cause a deterioration in hospital mortality. Objective: To examine the interaction between arrival time (time from onset of chest pain to arrival at hospital) and thrombolytic treatment in determining the early outcome of acute myocardial infarction. Methods: Prospective cohort study of 1723 patients with acute myocardial infarction who were potentially eligible for thrombolytic treatment (ST elevation on ECG; arrival time ≤ 12 hours). Results: All patients were eligible for thrombolysis but only 1098 (80%) received it. Patients who did not receive thrombolytic treatment were older (66 (58-73) v 61 (53-70) years, p < 0.001), more commonly female (32.1% v 24.8%, p < 0.01), and had higher frequencies of previous infarction (28.6% v 15.6%, p < 0.001) and left ventricular failure (37.5% v 26.9%, p < 0.01) than patients who received thrombolytic treatment. For the group as a whole, 30 day mortality was 11.7% and was unaffected by arrival time, but in patients who did not receive thrombolysis an arrival time of ≤ 6 hours was associated with significantly higher 30 day mortality than an arrival time of 6-12 hours (24.3% v 2.6%, p = 0.002). Conversely, in patients who did receive thrombolysis an arrival time of ≤ 6 hours was associated with a lower 30 day mortality than an arrival time of 6-12 hours (8.5% v 14.5%, p < 0.02). Conclusions: Shortening prehospital delay in acute myocardial infarction will tend to increase the risk profile of patients presenting to emergency departments. The data presented here indicate that this may increase hospital mortality if underutilisation of thrombolytic treatment among high risk groups is not diminished. [ABSTRACT FROM AUTHOR]